Characteristics of gender-related circadian arterial blood pressure in healthy adolescents.

SUMMARY OBJECTIVE: To define 24-h characteristics of arterial blood pressure in healthy adolescent girls and boys; to determine gender-related differences of blood pressure, its circadian pattern. MATERIAL AND METHODS: The 24-h blood pressure was monitored hourly in healthy girls (n=22, without no account for the menstrual cycle phase) and boys (n=22). Additionally, blood pressure of adolescent girls (n=15) was examined during different phases of their menstrual cycle (follicular, ovulation, and luteal). Blood pressure was monitored with an auto-cuff automatic outpatient blood pressure monitor. RESULTS: Investigation showed gender-related differences in 24-h blood pressure. Study results revealed the circadian blood pressure rhythm characterized by a period of low values during nighttime and an early morning increase in both adolescent groups. Nocturnal systolic blood pressure was higher (P<0.05) in boys than in girls in all phases of their menstrual cycle. Diurnal systolic blood pressure in boys was higher than in girls in their follicular phase (P<0.05). The day and night blood pressure differed between boys and girls (P<0.05). A dipping blood pressure pattern as a decrease in mean nighttime blood pressure as compared with mean daytime blood pressure was defined: 10.02+/-6.7% in girls (n=22) and 13+/-6.3% in boys (n=22), without gender-related differences (P>0.05). There were no differences in blood pressure dipping among girls' groups in different menstrual cycle phases (P>0.05). Adolescent boys showed a significant positive correlation between their mean diurnal blood pressure and height (P<0.05). CONCLUSION: The study proved gender-related arterial blood pressure differences in healthy adolescents. The results demonstrate the gender-specific circadian blood pressure rhythm pattern in both gender groups.

Sodium valproate stimulates potassium and chloride urinary excretion in rats: gender differences.

BACKGROUND: The diuretic effect of valproates and its relation to urinary potassium (K+) and chloride (Cl-) excretion have not yet been investigated, so the aim of this study was to evaluate the influence of a single dose of sodium valproate (NaVPA) on 24-h urinary K+ and Cl- excretion in young adult Wistar rats of both genders. For measurement of K+ in urine, the same animals and samples as in our earlier publication were used (Pharmacology 2005 Nov, 75:111-115). The authors propose a new approach to the pathophysiological mechanisms of NaVPA effect on K+ and Cl- metabolism. Twenty six Wistar rats were examined after a single intragastric administration of 300 mg/kg NaVPA (13 NaVPA-male and 13 NaVPA-female), 28 control intact Wistar rats (14 males and 14 females) were studied as a control group. The 24-h urinary K+, Cl-, creatinine and pH levels were measured. RESULTS: Total 24-h diuresis and 24-h diuresis per 100 g of body weight were found to be significantly higher in NaVPA-rats of both genders than in rats of the control group (p < 0.05). The data showed NaVPA to enhance 24-h K+ excretion in NaVPA-males and NaVPA-females with significant gender-related differences: 24-h K+ excretion in NaVPA-male rats was significantly higher than in control males (p = 0.003) and NaVPA-female rats (p < 0.001). Regarding the 24-h K+ excretion, NaVPA-female rats did not show a statistically significant difference versus females of the control group (p > 0.05). 24-h urinary K+ excretion per 100 g of body weight in NaVPA-male rats was significantly higher than in control males (p = 0.025). NaVPA enhanced Cl- urinary excretion: 24-h Cl- urinary excretion, 24-h urinary Cl- excretion per 100 g of body weight and the Cl-/creatinine ratio were significantly higher in NaVPA-male and NaVPA-female rats than in gender-matched controls (p < 0.05). 24-h chloriduretic response to NaVPA in male rats was significantly higher than in female rats (p < 0.05). CONCLUSION: NaVPA causes kaliuretic and chloriduretic effects with gender-related differences in rats. Further investigations are necessary to elucidate the mechanism of such pharmacological effects of NaVPA.